1. Field
One embodiment of the invention relates to a moving picture coding device and a moving picture coding method which perform compression coding on moving picture data depending on an algorithm, such as a moving picture experts group (MPEG), and a recording medium with a moving picture coding program recorded thereon.
2. Description of the Related Art
As commonly known, a moving picture coding device that relies on the MPEG system, etc., applies motion compensation prediction in blocks to moving picture data and codes a prediction error and a motion vector which have been obtained through this compensation prediction processing. Various improvements are conventionally available for enhancing the coding efficiency of the moving picture data in the moving picture coding device. Of such, a proposal using skip determination, which determines whether or not a prediction error after discrete cosine transform (DCT) and quantization of a block to be coded is equivalent to ‘0’ (zero), and if it is determined that the error is equivalent to ‘0’, in a case that a motion vector of a P picture is smaller than a first threshold, and in a case that a difference in size between a motion vector of a B picture and a motion vector in the next block of the B picture is smaller than a second threshold, processing of the block is omitted and the variable length coding of the block is omitted by replacing the motion vector with ‘0’, thereby enhancing the compression rate, has been disclosed (e.g., Jpn. Pat. Appln. KOKAI Publication No. 2001-251627).
However, in the method depending on the skip determination which has been proposed, in a case that In the P picture, it is determined that a prediction error of a quantization block in a macroblock (MB) is equivalent to ‘0’, in a case that the value of a motion vector is not larger than the first threshold, since the method determines that the block is a ship macroblock without exception, the determination may affect the following pictures. Further, in the B picture, in a case that it is determined that a prediction error of a quantization block in a macroblock is equivalent to ‘0’, and that a difference vector in the same direction is not larger than the second threshold, the method may deteriorates the picture quality if a quantization error is small.